"Each week it will increase a little bit," Arians said, per Fox Sports 910's Mike Jurecki. "He had a nice eight-yard per carry average. Chris (Johnson) is still the starter and we will keep bringing (David) along. He will have a vital role every week, just how big we will wait and see."

Johnson has shown a knack for the big play, taking an opening-week catch 55 yards for the score against the Saints. The third-rounder was clocked on the grab by Next Gen Stats going a league-best 22.05 mph.

Against the Bears on Sunday, the rookie plowed through Chicago for 42 yards off just five attempts, more than doubling the 3.6 yards per carry posted by CJ2K.

Arians clearly enjoys having a veteran runner to lean on, but he went out of his way to praise the rookie, saying: "He is a whole lot like Matt Forte. They have a glide mode and it is really fast. It's deceiving."

It's not just Johnson's work in the backfield. He's proven to be a triple threat, scoring as a runner, receiver and return man on this 108-yard jolt against the Bears:

At 6-foot-1, 224 pounds, Johnson gives the Cardinals a playmaking machine bound to steal snaps away from Andre Ellington -- and the rest of this backfield. If he keeps putting points on the board, he'll be Arizona's starter within weeks, if not sooner.